Designing a Sustainable Water Supply Strategy through Biobjective Mixed-Integer Linear Programming: A Case Study on Gaza

Palestine is water-stressed and prone to possible shocks in water supply. However, about one-third to one-half of the delivered water in the Palestinian territories is lost in the distribution network, highlighting the necessity of a cost-effective supply policy that also minimizes corrosion and health-related risks by achieving a maximum level of water quality. There must be a decision-making system to help managers review and measure the status quo and develop optimal allocation decisions to resolve the potential problems with supply and quality as much as possible. This research presents optimal resource allocation for the drinking water supply system (DWSS) to minimize the unit cost of supply in the system and the chloride concentration of the water supplied simultaneously. A bespoke biobjective mixed-integer linear programming (BOMILP) model was developed. The weighted sum method (WSM) based on the positive ideal solution (PIS) approach is utilized to tackle the biobjectiveness of the model in a Pareto sense. The model was implemented and validated using a case study of Gaza. The results suggest that the share of desalinated water resources in the supply network will increase by about 50% in the 2030-2035 period. Furthermore, we found that the unit cost of supply is highly sensitive to a decrease in resource capacities. Finally, the average quality of water supplied can deteriorate rapidly if demand surges. The model can successfully handle the complexity of effective utilization of resources and yield optimal decisions for policymakers.